Method of preparation of composition fabric material



Patented Oct. 11, 1949 METHOD OF PREPARATION OF COMPOSI- TIONFABRIC'MATERIAL Howard Snow and Julia D; Hill, Charlotte, N. 0.,

assignors to Southern Friction Materials Company, a corporation of NorthCarolina No Drawing. Application June 29, 1945, Serial N0.602,426

4 Claims.

This invention relates to impregnated fabric materials of the typeadapted for composition shoe soling, floor coverings, step treads,friction surfaces, and other related uses.

This is continuaticn-in-part of the copending applications Ser. No.467,620, filed December 2, 1942, now Patent No. 2,424,861, and Ser. No.490,877, filed June 15, 1943, refiled after allowance as applicationSerial No. 699,641, filed September 27, 1946, which was allowed April20, 1949.

We have discovered that an impregated flexible fabric material havingmany desirable properties may be obtained by impregnating fabricmaterial with a thermosetting resin composition and applying heat to theimpregated materialto remove solvent and harden and set (i. e. cure) theimpregnant in situ; pressure-abrading the impregnated material to removethe hard and brittle surface crust of impregnant which-forms during thecuring step, and thus render the fabric material softer, smooth,gripping, and flexible; and then finishing the impregnated andpressureabraded fabric material to augment the physical properties 'ofthe resulting composition fabric material.

An important feature of our invention is that smooth, gripping,attractive, composition fabric materials can be prepared in the mannerjust described from coarse, cheap cotton and even jute fabrics.Impregnated fabric materials prepared in this manner are smooth andflexible and have excellent wear and water resistance, and possess anappearance and texture which is unique in materials of this type.

The method of preparing the impregnated fabric materials of ourinvention as noted above, comprises three distinct stages of treatment:(1) impregnation, in which the fabric material is filled or bodied andconditioned for wear and water resistance and the like; (2)pressureabrading, in which the hard and brittle impregnant crust formedduring curing is removed to render the impregnated fabric materialflexible and to divest it of undesirable surface characteristics; and(3) finishing, in which the impregnated and pressure-abraded fabricmaterial is treated to supplement and enhance the physical propertiesand appearance of the impregnated and pressure-abraded fabric material.For certain applications, such as for shoe soling friction surfaces, thecomposition fabric material of our invention may be used after the firsttwo stages of treatment.

The impregnation is carried out, as previously tion. While a substantialvariety of materials are available for this purpose, the particular ma-;terial selected must conform to certain critical chlorides, and soforth, which are adapted primentioned, with a thermosetting resincomposimarily for use as coatings and will not penetrate adequately forsatisfactory use as impregnants.

Secondly, the particular impregnant selected :must be of a character tostand up during the subsequent pressure-abrading operation. As describedmore in detail below, the pressure-abrading operation results in thegeneration of considerable heat, and the impregnant will smear and foulthe abrading means if it is not adapted for treatment in this manner.The impregnant used should accordingly form a non-sticky surface crustupon curing which will not become-tacky during the pressure-abrasion.Thermoplastic resin compositions or impregnants having an asphalt orcoal tar base, for instance, are not suited for use according to ourinvention because they cannot be pressure-abraded satisfactorily.

In addition to the foregoing requirements, the particular impregnantselected must alsobe capable of providing the ultimate physicalproperties desired in the finished fabric material, such as flexibility,and wear and water resistance.

A specific example of a commercially advantageous impregnatingcomposition particularly suited for use in preparing the impregnatedfabric material of our invention comprises a relatively hard phenolicresin, petroleum polymers, and a drying oil. Representative percentagecompositions of an impregnant of this type are as follows:

Fabric material impregnated with Composition A above is characterized byhigh flexibility. Fabric material impregnated with Composition 0- has 1material.

3 greater body, and wear and water resistance, at the expense, somewhat,of flexibility. Composition B results in an impregnated fabric in whichthe properties of flexibility and body are intermediately balanced.

The hard resin component of the above compositions provides the desiredtoughnes and wear resistance that characterizes the impregnated fabricmaterial of our invention. Besides the phenolic resins indicated aboveother suitable materials for use as the resin component are: modifiedphenolic resins, such as Amberol resin and Phenac 622N; resinates suchas Zirex which is a zinc resinate; neutralized rosin; ester gum; andfused Congo gum.

The petroleum polymer component, sometimes referred to as petroluempitch, functions as a plasticizer and impregnation accelerator orintrofier in the above compositions. This component also improves theimpregnant-to-fabric bond and augments the oleaginous property of thetreated A notable difficulty in impregnating fabric materials,particularly cotton fabrics, is the problem of obtaining adequatepenetration and adherence of the impregnant in the fabric structure.Resins and oils will not accomplish this result satisfactorily alone.Asphalt tends to act as a penetrating supplement, but as mentioned aboveit cannot be employedin effective quantities according to our inventionbecause it will not stand up under pressure-abrasion after curing. Theintrofying characteristic of petroleum polymers are unique forapplication according to the present invention.

Petroleum polymers, as they are known to the trade, are composed ofpolymerized olefinic hydrocarbons of petroleum origin. A specificexample is Pur-O-Resin, (No. 2138) which is manufactured by the Pure OilCo. and has the following published characteristics; Per cent solids,85% minimum; viscosity 275-325 at 210 F.; iodine value 200 minimum,saponification value less than one; reactive with drying oils; boilingrange begins at about 450 F. The term petroleum polymers is used in thisapplication to include the above described material and other materialsof similar nature and characteristics.

To provide the desired flexibility and tensile strength in the treatedmaterial and to modify somewhat the hardening properties of the resincomponent, a dryin oil is included in the above compositions in a majorproportion. Illustrative examples are: linseed oil; China-wood oil;oiticica oil; perilla oil; soybean oil; dehydrated castor oil; and,cashew-nut shell oil. The variious commonly available synthetic dryingoils may also be used such as: Highland G oil, which is a derivative ofnative linseed oil with the break removed, and is manufactured by theHighland Chemical Company, New York, N. Y.; and Hyodol Glycerides whichis manufactured by the Werner G. Smith 00., Cleveland, Ohio, and isprepared by splitting the glycerin from fish oil, such as sardine oil,followed by fractionating the fish oil acids and finally re-esterifyingthe fraction consisting partially of culpanodonic acids to obtain aproduct which is the glyceride of culpanodonic acid and similar highlyunsaturated fatty acids.

The impregnating composition is thinned with a suitable organic solventto obtain the desired fluidity for impregnation. Various commercialsolvents, such as xylol and benzol, may be used for this purpose. Alsoany of the materials Varsol, Solvesso, and V. M. 8: P. Solvent which aremanufactured by the Standard Oil Company of New Jersey, and AmscoSpirits manufactured by the American Mineral Spirits Company, may beused. All of these trade-mark products are well-known, light petroleumdistillates and are widely available in commercial quantities.

Any of the usual driers such as lead or manganese naphthenate may beused with the above compositions as indicated to facilitate the curingprocess.

The impregnation treatment is carried out by suitably mixing the resin,petroleum polymer, and drying oil components of the impregnatingcomposition in the proportions desired as indicated above, and heatingthe components together until they react and combine with each other anduntil the resulting solution has reached the proper viscosity. Thesolvent and any indicated driers are then added and thoroughly mixedwith the above heat reaction product of resin, petroleum pitch anddrying oil to form the complete composition.

The impregnation is carried out with either a single dip or multiple dipprocedure. Usually it is desirable to employ more than one dip becausethere is a practical limit from the standpoint of viscosity to theamount of impregnant that can be taken up by the fabric material in anyone dip, and as an impregnant solids concen tration of the order of 40%should be obtained in most cases to condition the treated fabricmaterial with proper physical properties, a multiple dip process isnormally indicated. The percentage compositions indicated above areadapted for two-dip treatments. If otherwise desirable, however, it ispossible to increase the impregnant solids concentration of the treatedfabric material obtained in a one dip process by using an impregnatingcomposition of high solids content and by carrying out the impregnationat higher temperatures to cut the viscosity.

In conducting the impregnation treatment the fabric material is dippedor immersed in the impregnating composition maintained at a temperatureof about F. After dipping, the impregnated fabric material is placed ina drying chamber and dried for about one and onehalf to two hours atabout 275 F.

After drying the initially impregnated fabric material is dipped asecond time and then allowed to air dry. The impregnated fabric materialis then cured at a temperature of the order of 200 F. to 275 F. forabout 24 to 36 hours.

The impregnation treatment is followed, as previously noted, with apressure-abrading operation to remove the crust of hardened impregnantformed during the curing process so as to render the impregnated fabricmaterial flexible and condition its surfaces. The impregnated fabricmaterials are hard and stiii after curing by virtue of the impregnantcrust formed during this step. Moreover, this curing crust follows thesurface irregularities of the original fabric material and presents avery undesirable surface. Pressure-abrasion is necessary to remove thiscuring crust properly. Other types of abrasion, such as a wire brush andsand blast, will not give satisfactory results.

Also, as described more in detail below, it is necessary to lubricatethe pressure-abrasion operation, as with water, to obtain the maximumbenefit from this treatment. Wet pressurethe rolls. justable to"vary theclearance dimension be- The pressure-abrasion may be carried out on aconventional endless bed dimensional sander. A sander arranged for fixedroll clearance rather than fixed pressure ispreferred. Reference is madeto the copending application of Snow and Pickard, Ser. No. 530,648,filed April 12, 1944, now- Patent No. 2,402,689, for a disclosure ofpressureabrading apparatus of this type adapted for use in the presentinstance. ."dim'e'nsional sander comprises a plurality of abrading rolls(suitably, in this instance, three) Generally described, a

arranged above a bed on which a flat surfaced sup port or carriage ismounted to be moved under the rolls. Material to be pressure-abraded islaid on the movable carriage and passed under The abrading rolls arevertically adtween the rolls and the movable carriage. Water is sprayedon the rolls during operation to lubricate the abrasion and keep therolls clean.

In carrying out the pressure-abrading operation, the impregnated andcured fabric material is heated for about minutes at about 250 F. andthen placed in a heated Water bath, such as a container with watercontinuously heated by live steam. The treated fabric material isallowed to remain in this hot water bath for a nated fabric material sothat it may be pressureabraded more easily.

The wet and softened impregnated fabric material is thenpressure-abraded to remove the impregnant curing crust. This operationmay be carried out by either batch or continuous procedures as describedin the above mentioned copencling application, Ser. No. 530,648. Animportant feature of this operation is the water- I lubricated pressureapplied as a result of the fixed clearance maintained while the abradingis effected. This pressure results from the fact that the abrading rollsare necessarily adjusted to less than the thickness dimension of theimpregnated fabric material in order to remove the hardened impregnantcrust, so that considerable pressure is applied to the treated fabricmaterial as it is passed under the abrading rolls'and thewaterlubrication allows a high pressure/abrasion ratio. to be used. Thispressure produces a supplemen- *tal' calendering effect during-theabrading operationwhich substantially improves the smoothness anduniformity of the abraded surfaces.

As previously mentioned, the impregnant tends 1 to harden and set inconformity with the'surface irregularities of the original fabricmaterial. In view of this circumstance, it is highly advantageous toproduce a flow at the surface of the impregnated fabric material to fillup the depressions-occasioned by these irregularities as well as -leveloff the high spots.

Pressure-abrasion, particularly when the fabric material-is preheated asdescribed-above, accomplishes this result in a very satisfactory manner;and, as agenera-lprop-m 'ositioni 'the greater the pressuresapplldz thebet- -=ter arethe results obtained.

Care must be taken iin" this iconnectionphow- 'ev'erfthat napping ofnign sp'o'ts does not occur as the pressure :is="increased. 'I he abovedescribed preliminary heat and 'watertreatment; as"w'ell as the waterspray played on the abrading rolls-has animportant efiectiirobviating"this resultiby lubricating the -*-'pressure'-abrading1-operation.

lubricating effe'ct maybe augmented-by ineluding a'waxy emulsion in thewater bath.- illustfative example is'the' use'of a dispersi-ble-wax thewater bath in combinationwith an aimn um acetatewaterrepellant"materiahsuch as'the product known commerciallyas"Paratex"which"is sold by the' Ch'arlotte Chemical Laboratories, Inc., Charlotte, N.C. Also, asdesribed-Iiidtedn detail below, the impregnation treatmentmay- 'be modified to -includethe use I ofmaterials -tofa'cili tate thepressure-abrading operations.

The piessure-abrasion method described above removes" the impreg-nantcuring crust quickly and 'without damaging the fabric -material;- and':-pro duces' smooth, filled surfaces which-are uniform and even. In mostcases"-itwill be advantageous to pressure-abrade i the impregnatedfabric' materialfon' both sides, althOugh it may 'only -"be necessary toabrade one side -inzparticular instances.

When-fabrics havinga high degree of "pebble,

- such 'as' 'jute "fabricsor naught ducksg' are' em- -ploy ed accordingto our inventiomthe surface irregulari-ties 0f the impregnated and curedfabrics are pronounced and' require treatment by pressure abrasion to a"correspondingly? greater 'extent. Under these circumstances; we havefoundth'at 1 the process of ourinvention is facilitated"byincluding apigment supplement' -iri the impregnation treatment. The pigment may beselected to match the color of the fabric being treated,-for example,white diatomaceous silica may be used in treating cotton duck, orcolored pigments may be used if colored effects are desired.

It appears that when pigment is used in this manner, the pigment isdisposed by a filtering effect during impregnation so that it tends tofill up the surface depressions of the'impregn'ated fabric occasioned bythe pebble of the fabric being treated, and thus makes it possible toobtain a desirable surface after impregnation and curing with lesssevere pressure-abrasion. Also; the

pigment has the effect of excluding air from'the body of the fabricmaterial during curing so that the darkened curing crust issubstantiallyrestricted to the surfaces of the treated fabric-materialand may be easily removed. The use of pigment has the further advantagethat it=allows soapy water to be used to lubricate'the pressureabrasionoperation. Soapy water effects adecided improvement in the lubricationobtained during pressure-abrasion, but it normally has-the undesirableeffect of washing the treated fabric pores clean so that the pebbleis'accentuated. The incorporation of pigment obviates this effect andresults in a Well filled and attractive surface after pressure-abrasion.

The impregnation treatment is modified to" include a pigment supplementby incorporating ground pigment in the ratio of about one part'ofpigment by weight to two parts ofimpregnant ing operation to obtain afinished material of unique appearance and texture.

Also, the finishing treatment enhances the physical properties of thecomposition fabric material obtained. The impregnated andpressureabraded fabric material, for example, appears to have anaffinity for extraneous materials, such as dirt, metal filings, and oiland grease, and exhibits a tendency to pick up such foreign matter. Thistendency to pick up foreign matter is entire- 1y eliminated by thefinishing treatment.

The finishing treatment may take the form of a sizing treatment, acoating treatment, or a combined sizing anda coating treatment. If asizing treatment isto be employed, such materials as shellac, casein,zein, phenolic and urea resins, and so forth may be used as the size.The sizing material may be used with or without a suitable plasticizerdepending upon whether a rigid or flexible sizing is desired. We haveobtained very satisfactory results with plasticized urea-formaldehyderesin (either water or solvent soluble type) for flexible sizings, andwater soluble phenolic resin for rigid sizings.

The sizing operation is carried out by dipping the impregnated andpressure-abraded fabric material in the sizing composition and thenrunning it through squeeze rollers, after which the material is dried ata temperature of about 200 F. for about four to eight hours. Thesurfaces of the sized fabric material are entirely sealed by the sizingoperation, and the sizing results in increased mechanical strength andsubstantially improved wear resistance.

The sizing treatment may also be adapted to provide a coating effect ifdesired. For this purpose the sizing composition is adjusted to arelatively high solids concentration, such as 50% or more (or severalapplications at 30-35% solids concentration are used) and is applied toone or both sides of the impregnated and pressureabraded fabric materialby any regular coating vmethod such as a brush or knife, a metered rollcoater, or a spray gun. The fabric material is then baked or dried asabove for three or four hours.

.nomically, and the reverse side of the material is better conditionedand more attractive as a result of a dip sizing operation when only oneside of the material is to be provided with a coated appearance.

Suitable materials for use in the coatin treatment are the variouscellulose coating compositions, such as ethyl-cellulose, plasticizedzein, and other lacquers. The coating may be applied by the usualcoating procedures with a brush or knife or other coating applicator,after which it may be baked or otherwise dried according to the methodscommonly used in the coating art.

We claim:

.1; The method of preparing a composition composition in situ, thenwetting the impre'gnated fabric with water and pressure-abrading thesurfaces of said fabric While wet to remove the surface crust ofimpregnant formed during curing whereby the impregnated fabric isdivested of undesirable surface characteristics and rendered relativelyflexible.

2. The method of preparing a composition fabric material which comprisesbodying a woven organic fibrous fabric by impregnation with athermosetting resin composition, comprising by weight, about 15-20% ofan oil-soluble phenolaldehyde resin, 25-40% of a petroleum pitchcomposed of polymerized olefinic hydrocarbons and having a minimumiodine number of about 200 and a boiling range beginning at about 450and 45-55% of a drying oil, heating, the fabric to cure the resincomposition in situ, and then wetting the impregnated fabric with Waterand pressure abrading the surfaces of said fabric while wet at a highpressure/abrasion ratio to remove the surface crust of impregnant formedduring curing to render the fabric relatively flexible and divest it ofundesirable surface characteristics and then treating the impregnatedand pressureabraded fabric with a surface finishing composition to sealthe surfaces of said fabric.

3. The method of preparing a composition fabric material which comprisesimpregnating a woven, organic fibrous fabric with a thermosetting resincomposition, comprising by weight. about 15-20% of an oil-solublephenol-aldehyde resin, 25-40% of a petroleum pitch composed ofpolymerized olefinic hydrocarbons and having a minimum iodine number ofabout 200 and a boilil'lg range beginning at about 450 F., and 45-55% ofdrying oil, heating the fabric to cure the resin composition in situ,pressure-abrading the surfaces of the cured fabric While Wetting saidsurfaces with water to remove the surface crust of the impregnant formedduring curing whereby the impregnated fabric is divested of undesirablesurface characteristics and rendered relatively flexible, and thensizing the impregnated and pressure-abraded "fabric to seal the surfacesthereof.

4. The method of preparing a composition fabric material which comprisesimpregnating a woven, organic fibrous fabric with a thermosetsurfacecharacteristics and rendered relatively flexible, sizing the impregnatedand pressureabraded fabric to seal the surfaces thereof, and applying acoating to at least one of the surfaces 10 to augment the appearancecharacteristics of the Number Name Date composition fabric material.1,766,932 Novak June 24, 1930 HOWARD SNOW. 1,927,985 Leahey Sept. 26,1933 JULIA D. HILL. 2,138,876 Novak Dec. 6, 1938 5 REFERENCES CITEDOTHER REFERENCES 1 ds et a1. Handbook of Plastics D. Van. The followingreferences are of record in the file of this patent: Nostrand, New York,1943, pp. 217-218.

UNITED STATES PATENTS 10 Number Name Date 1,728,172 Bendix Sept. 17,1929

